Multi-layer porous film material

ABSTRACT

A surgical implant includes at least two porous film layers each having a plurality of pores. The porous film layers are in a stacked configuration and are interconnected to one another at a plurality of attachment points to define at least one void between the porous film layers.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application which claims the benefit of and priority to U.S. patent application Ser. No. 13/690,445, filed on Nov. 30, 2012, the entire disclosure of which is hereby incorporated by reference herein.

BACKGROUND 1. Technical Field

The present disclosure relates to medical devices, and more particularly, to multi-layered porous films for use as surgical implants.

2. Background of Related Art

The use of medical devices, and more specifically, implants, is known. Surgical implants include, for example, meshes for hernia repair, buttresses for staple line reinforcement, patches and sealants for repair of tissue defects and hemostasis, scaffolds for tissue integration, and other wound closure and tissue repair devices. The performance requirements of each of these implants are different, and thus, the material and construction of these implants vary and are specific to the surgical procedure being performed.

It would be advantageous to provide a surgical implant that can be used in a variety of surgical applications, wherein the properties of each layer of the implant can be controlled by material selection, pore size, and pore distribution, and the layered construction of the implant can be tailored to produce an implant having the desired mechanical strength and tissue compatibility necessary for favorable host interaction.

SUMMARY

A surgical implant of the present disclosure includes at least two porous substrates each having a plurality of openings. The porous substrates are in a stacked configuration and are interconnected to one another at a plurality of attachment points to define at least one void between the porous substrates.

According to an aspect of the present disclosure, a surgical implant includes a first porous film layer including a plurality of pores layered on top of a second porous film layer including a plurality of pores. The first and second porous film layers are interconnected to one another at a plurality of attachment points that define at least one void within the surgical implant between the first and second porous film layers. In embodiments, the attachment points are substantially evenly spaced about the surgical implant.

The first and second porous film layers may be fabricated from a biodegradable, a non-degradable material, or combinations thereof. In embodiments, the first and second porous film layers are substantially planar. In other embodiments, the first and second porous film layers may be non-planar and shaped to conform to a specific tissue surface. The first and second porous film layers may have the same or a different thickness, the same or a different elasticity modulus, and/or the same or a different degree of porosity. In embodiments, the first and second porous film layers may be uniaxially oriented in the same or different directions.

The surgical implant may include an adhesion barrier layer and/or an adhesion layer applied to an outer surface of the first and/or second porous film layers. The adhesion barrier layer and adhesion layer may be provided as films. The surgical implant may also include a filler material disposed within the openings of the first porous layer, the openings of the second porous film layer, and/or the voids between the first and second porous film layers. In embodiments, the filler material is a drug. In some embodiments, the filler material is a hydrogel.

The surgical implant may include a third porous film layer including a plurality of pores. The third porous film layer is interposed between the first and second porous film layers, and is interconnected by at least one attachment point with at least one of the first and second porous film layers.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing objects and advantages of the disclosure will become more apparent from the reading of the following description in connection with the accompanying drawings, in which:

FIGS. 1A and 1B are perspective and cross-sectional views, respectively, of a surgical implant in accordance with an embodiment of the present disclosure;

FIG. 1C is a cross-sectional view of the surgical implant of FIGS. 1A and 1B including a filler material in accordance with another embodiment of the present disclosure;

FIG. 2A is a perspective view of an embodiment of a surgical implant of the present disclosure for use with a circular surgical stapling device;

FIG. 2B is a front, perspective view of the surgical implant of FIG. 2A;

FIG. 3 is a perspective view of an embodiment of a surgical implant and a linear surgical stapling apparatus in accordance with another embodiment of the present disclosure;

FIG. 4 is a partial, cross-sectional view of a surgical implant in accordance with a further embodiment of the present disclosure;

FIG. 5A is a partial, cross-sectional view of a surgical implant in accordance with another embodiment of the present disclosure;

FIG. 5B is a partial, cross-sectional view of the surgical implant of FIG. 5A including an adhesion barrier in accordance with an embodiment of the present disclosure;

FIG. 6 is a partial, cross-sectional view of a surgical implant in accordance with yet still another embodiment of the present disclosure;

FIG. 7 is a perspective view of a surgical implant in accordance with another embodiment of the present disclosure;

FIG. 8 is a cross-sectional view of a surgical implant in accordance with yet another embodiment of the present disclosure; and

FIG. 9 is a cross-sectional view of a surgical implant in accordance with another embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to a multi-layered implant including at least two porous film layers joined at attachment points for use in a variety of surgical applications. The porous nature of the films and the multi-layered construction of the implant provide spaces for fluid transfer and filling, tissue ingrowth, and loading of filler materials, such as drug or biologic factors.

The following discussion includes a description of the presently disclosed surgical implant and exemplary embodiments of construction and use in accordance with the principles of the present disclosure. The presently disclosed surgical implants may be any medical device, such as scaffolds, grafts, patches, slings, pledgets, growth matrices, drug delivery devices, wound plugs, and, in general, soft tissue repair devices and surgical prostheses. It should be understood that the device may also be utilized as topically applied medical products, such as wound dressings, coverings, and the like, that can be used in medical/surgical procedures.

Referring now to the figures, wherein like components are designated by like reference numerals throughout the several views, FIGS. 1A and 1B illustrate a surgical implant 10 including at least two porous substrates 12 overlying one another, e.g., first porous film layer 12 a and second porous film layer 12 b. Each of the porous substrates 12 includes openings 14, illustrated as openings 14 a and 14 b, respectively, such as pores, voids, or holes over at least a portion of a surface thereof. The porous film layers 12 a and 12 b may be formed by any suitable process, such as cast extrusion, molding, co-extrusion, or blown film processes. While the surgical implant 10 of the present disclosure is formed solely from porous film layers, it is envisioned that a surgical implant of the present disclosure may also include a porous substrate in the form of a foam or fibrous layer.

The porous substrates are fabricated from any biodegradable and/or non-degradable material. The term “biodegradable” as used herein is defined to include both bioabsorbable and bioresorbable materials. By biodegradable, it is meant that the material decomposes, or loses structural integrity under body conditions (e.g., enzymatic degradation or hydrolysis), or is broken down (physically or chemically) under physiologic conditions in the body, such that the degradation products are excretable or absorbable by the body. Absorbable materials are absorbed by biological tissues and disappear in vivo at the end of a given period, which can vary, for example, from hours to several months, depending on the chemical nature of the material. It should be understood that such materials include natural, synthetic, bioabsorbable, and/or certain non-absorbable materials, as well as combinations thereof.

Representative natural biodegradable polymers which may be used to form a porous substrate include: polysaccharides such as alginate, dextran, chitin, chitosan, hyaluronic acid, cellulose, collagen, gelatin, fucans, glycosaminoglycans, and chemical derivatives thereof (substitutions and/or additions of chemical groups including, for example, alkyl, alkylene, amine, sulfate, hydroxylations, carboxylations, oxidations, and other modifications routinely made by those skilled in the art); catgut; silk; linen; cotton; and proteins such as albumin, casein, zein, silk, and soybean protein; and combinations such as copolymers and blends thereof, alone or in combination with synthetic polymers.

Synthetically modified natural polymers which may be used to form a porous substrate include cellulose derivatives such as alkyl celluloses, hydroxyalkyl celluloses, cellulose ethers, cellulose esters, nitrocelluloses, and chitosan. Examples of suitable cellulose derivatives include methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, cellulose acetate phthalate, carboxymethyl cellulose, cellulose triacetate, cellulose sulfate sodium salt, and combinations thereof.

Representative synthetic biodegradable polymers which may be utilized to form a porous substrate include polyhydroxy acids prepared from lactone monomers (such as glycolide, lactide, caprolactone, ε-caprolactone, valerolactone, and δ-valerolactone), carbonates (e.g., trimethylene carbonate, tetramethylene carbonate, and the like), dioxanones (e.g., 1,4-dioxanone and p-dioxanone), 1,dioxepanones (e.g., 1,4-dioxepan-2-one and 1,5-dioxepan-2-one), and combinations thereof. Polymers formed therefrom include: polylactides; poly(lactic acid); polyglycolides; poly(glycolic acid); poly(trimethylene carbonate); poly(dioxanone); poly(hydroxybutyric acid); poly(hydroxyvaleric acid); poly(lactide-co-(ε-caprolactone-)); poly(glycolide-co-(ε-caprolactone)); polycarbonates; poly(pseudo amino acids); poly(amino acids); poly(hydroxyalkanoate)s such as polyhydroxybutyrate, polyhydroxyvalerate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polyhydroxyoctanoate, and polyhydroxyhexanoate; polyalkylene oxalates; polyoxaesters; polyanhydrides; polyester anyhydrides; polyortho esters; and copolymers, block copolymers, homopolymers, blends, and combinations thereof.

Some non-limiting examples of suitable non-degradable materials from which a porous substrate may be made include: polyolefins such as polyethylene (including ultra high molecular weight polyethylene) and polypropylene including atactic, isotactic, syndiotactic, and blends thereof; polyethylene glycols; polyethylene oxides; polyisobutylene and ethylene-alpha olefin copolymers; fluorinated polyolefins such as fluoroethylenes, fluoropropylenes, fluoroPEGSs, and polytetrafluoroethylene; polyamides such as nylon, Nylon 6, Nylon 6,6, Nylon 6,10, Nylon 11, Nylon 12, and polycaprolactam; polyamines; polyimines; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, and polybutylene terephthalate; polyethers; polybutester; polytetramethylene ether glycol; 1,4-butanediol; polyurethanes; acrylic polymers; methacrylics; vinyl halide polymers such as polyvinyl chloride; polyvinyl alcohols; polyvinyl ethers such as polyvinyl methyl ether; polyvinylidene halides such as polyvinylidene fluoride and polyvinylidene chloride; polychlorofluoroethylene; polyacrylonitrile; polyaryletherketones; polyvinyl ketones; polyvinyl aromatics such as polystyrene; polyvinyl esters such as polyvinyl acetate; etheylene-methyl methacrylate copolymers; acrylonitrile-styrene copolymers; ABS resins; ethylene-vinyl acetate copolymers; alkyd resins; polycarbonates; polyoxymethylenes; polyphosphazine; polyimides; epoxy resins; aramids; rayon; rayon-triacetate; spandex; silicones; and copolymers and combinations thereof.

A porous substrate of a surgical implant of the present disclosure may be provided in a variety of shapes and sizes to accommodate a variety of defects and tissue fascia that may need repair. Generally, a porous substrate is substantially planar and configured as a sheet that may be arranged in a layered or stacked configuration. A porous substrate, however, may, in embodiments, include non-planar surfaces that are sized and shaped to conform to a tissue surface. A porous substrate can be produced at a desired size and shape, or may be cut to a suitable size and shape for the envisaged application of use. A porous substrate may be provided in a variety of thicknesses depending upon the properties desired, e.g., stiffness and strength. In embodiments, a porous substrate (individual layer) may be from about 25 μm to about 500 μm thick, in some embodiments, from about 40 μm to about 250 μm thick, and in other embodiments, from about 50 μm to about 100 μm thick.

The openings in a porous substrate of a surgical implant of the present disclosure may be present as a surface characteristic or a bulk material property, which partially or completely penetrates the porous substrate, and may be uniformly or randomly distributed across portions thereof. In some embodiments, the openings do not extend across the entire thickness of a porous substrate, but rather are present at a portion of the surface thereof. Those skilled in the art reading the present disclosure may envision a variety of distribution patterns and configurations of the openings in a porous substrate. It is envisioned that the porous substrate may, in embodiments, be partially or substantially non-porous.

The porous substrate may be rendered porous by any number of processes, including, for example, die rolling; laser micro-perforating; solvent leaching of salt, sugar, or starch crystals; among other mechanical, electrical, and chemical processes within the purview of those skilled in the art. The openings of the porous substrate may be sized and configured to permit fibroblast through-growth and ordered collagen laydown, resulting in integration of the surgical implant into the body. In embodiments, the openings may be from about 50 micrometers to about 500 micrometers in diameter, in some embodiments, from about 100 micrometers to about 400 micrometers in diameter, and in yet other embodiments, from about 200 micrometers to about 300 micrometers in diameter. In embodiments, the openings may cover from about 20% to about 80% of the area of a porous substrate, in some embodiments, from about 30% to about 70% of the area, in yet other embodiments, from about 40% to about 60% of the area of a porous substrate. It should be understood that different thicknesses, weights, and porosities of a porous substrate may be selected by varying material selection and manufacturing conditions.

Referring again to FIGS. 1A and 1B, first and second porous film layers 12 a and 12 b are joined at spaced attachment points 16 to create voids or pockets 18 between the first and second porous film layers 12 a and 12 b. The first and second porous film layers 12 a and 12 b may be joined by a number of bonding processes, including ultrasonic welding and adhesive bonding, among other bonding techniques within the purview of those skilled in the art. In embodiments, the attachment points 16 are of substantially similar size and/or shape and may be positioned at substantially evenly spaced intervals across first and second porous film layers 12 a and 12 b, forming a plurality of voids 18 between the first and second porous film layers 12 a and 12 b. In some embodiments, the attachment points 16 may be provided around the entire periphery of the implant 10, forming a single, large void 18 between the first and second porous film layers 12 a and 12 b. In other embodiments, the size, shape, and/or position of the attachment points 16 may vary.

In embodiments, as illustrated in FIG. 1C, the openings 14 and/or voids 18 may be loaded with filler material(s) 19, such as drugs or biologic factors, among other secondary materials such as foams, hydrogels, adhesives, sealants, salts, sugars, etc. In embodiments, the filler material 19 may fill about 5% to about 100% of the openings 14 and/or voids 18 of the surgical implant 10, in some embodiments, from about 10% to about 80% of the openings 14 and/or voids 18, and in yet other embodiments, from about 25% to about 75% of the openings 14 and/or voids 18. The filler material 19 may be incorporated into the surgical implant 10 during fabrication, or after the surgical implant 10 is formed. The implant or medical device can have spaced, intermittent attachment points that are circular, linear, or have any shape. The attachment points can form separate pockets in the implant or medical device, or render the implant or medical device with a quilt-like configuration.

In embodiments, filler material 19 may include hydrogels which may be used as a means to absorb blood and as carriers of thrombogenic agents for blood clotting and hemostasis at wound sites. Hydrogels can be modified with any number of conjugated molecules such as cell adhesion proteins, growth factors, peptides, and endogenous growth factor capturing molecules, such as heparin sulfate, to promote tissue ingrowth and healing. In embodiments, the filler material 19 may include releasable factors that have an associated binding interaction that will release agents by unbinding and diffusion, or filler material degradation.

Examples of filler materials 19 which may be utilized in accordance with the present disclosure for example, include: anti-adhesives; antimicrobials; analgesics; antipyretics; anesthetics; antiepileptics; antihistamines; anti-inflammatories; cardiovascular drugs; diagnostic agents; sympathomimetics; cholinomimetics; antimuscarinics; antispasmodics; hormones; growth factors; muscle relaxants; adrenergic neuron blockers; antineoplastics; immunogenic agents; immunosuppressants; gastrointestinal drugs; diuretics; steroids; lipids; lipopolysaccharides; polysaccharides; platelet activating drugs; clotting factors; cancer treating chemical agents; and enzymes. It is also intended that combinations of filler materials may be used.

Other filler materials 19 include: local anesthetics; non-steroidal antifertility agents; parasympathomimetic agents; psychotherapeutic agents; tranquilizers; decongestants; sedative hypnotics; steroids; sulfonamides; sympathomimetic agents; vaccines; vitamins; antimalarials; anti-migraine agents; anti-parkinson agents such as L-dopa; anti-spasmodics; anticholinergic agents (e.g., oxybutynin); antitussives; bronchodilators; cardiovascular agents, such as coronary vasodilators and nitroglycerin; alkaloids; analgesics; narcotics such as codeine, dihydrocodeinone, meperidine, morphine and the like; non-narcotics, such as salicylates, aspirin, acetaminophen, d-propoxyphene and the like; opioid receptor antagonists, such as naltrexone and naloxone; anti-cancer agents; anti-convulsants; anti-emetics; antihistamines; anti-inflammatory agents, such as hormonal agents, hydrocortisone, prednisolone, prednisone, non-hormonal agents, allopurinol, indomethacin, phenylbutazone and the like; prostaglandins; cytotoxic drugs; chemotherapeutics, estrogens; antibacterials; antibiotics; anti-fungals; anti-virals; anticoagulants; anticonvulsants; antidepressants; antihistamines; and immunological agents.

Examples of yet other suitable filler materials 19 include: viruses and cells; peptides, polypeptides and proteins, as well as analogs, muteins, and active fragments thereof; immunoglobulins; antibodies; cytokines (e.g., lymphokines, monokines, chemokines); blood clotting factors; hemopoietic factors; interleukins (IL-2, IL-3, IL-4, IL-6); interferons (β-IFN, α-IFN and γ-IFN); erythropoietin; nucleases; tumor necrosis factor; colony stimulating factors (e.g., GCSF, GM-CSF, MCSF); insulin; anti-tumor agents and tumor suppressors; blood proteins such as fibrin, thrombin, fibrinogen, synthetic thrombin, synthetic fibrin, synthetic fibrinogen; gonadotropins (e.g., FSH, LH, CG, etc.); hormones and hormone analogs (e.g., growth hormone); vaccines (e.g., tumoral, bacterial and viral antigens); somatostatin; antigens; blood coagulation factors; growth factors (e.g., bone or nerve growth factor, insulin-like growth factor); bone morphogenic proteins; TGF-B; protein inhibitors; protein antagonists; protein agonists; nucleic acids, such as antisense molecules, DNA, RNA, RNAi; oligonucleotides; polynucleotides; and ribozymes. It is contemplated that the filler material can be released over time. The filler material may be released or degrade over time or may be non-degradable.

Exemplary embodiments of construction and use of the present surgical implants are provided below. While embodiments are illustrated and described with respect to specific surgical applications, it should be understood that the surgical implants may be used in any of a variety of surgical procedures, and that elements and features illustrate or described in connection with one exemplary embodiment may be combined with elements and features of another exemplary embodiment.

Surgical implants of the present disclosure may be utilized in surgical stapling procedures. As illustrated in FIGS. 2A and 2B, there is disclosed an exemplary surgical stapling apparatus or surgical stapler 100 (i.e., a circular stapler) for use in stapling tissue and applying a surgical implant, or surgical buttress 110, of the present disclosure to tissue. Surgical stapling apparatus 100 generally includes a handle assembly 120 having at least one pivotable actuating handle member 122, and an advancing member 124. Extending from handle member 120, there is provided a tubular body portion 126 which may be constructed so as to have a curved shape along its length. Body portion 126 terminates in a staple cartridge assembly 130 which includes an annular array of staple retaining slots 132 having a staple (not shown) disposed in each one of staple retaining slots 132. Positioned distally of staple cartridge assembly 130 there is provided an anvil assembly 140 including an anvil member 142 and a shaft 144 operatively associated therewith for removably connecting anvil assembly 140 to a distal end portion of stapling apparatus 100.

Reference may be made to commonly owned U.S. Pat. No. 5,915,616 to Viola et al., entitled “Surgical Fastener Applying Apparatus,” the entire contents of which is incorporated herein by reference, for a detailed discussion of the construction and operation of an annular stapling device.

A surgical buttress 110, in accordance with the present disclosure, is positioned about the shaft 144 of the anvil assembly 140. Surgical buttress 110 includes porous layers 112 each having openings 114 disposed through at least a portion thereof, and a central aperture 113 for positioning the surgical buttress 110 about the shaft 144 of the anvil assembly 140. It should be understood that while the surgical buttress 110 is shown as being associated with the anvil assembly 140, the surgical buttress 110 may, alternatively or additionally, be associated with staple cartridge assembly 130. Surgical buttress 110 may be configured into any shape, size, or dimension suitable to fit any surgical stapling, fastening, or firing apparatus

Surgical buttress 110 is provided to reinforce and seal staple lines applied to tissue by surgical stapling apparatus 100. The openings 114 and/or voids (not shown, similar to voids 18) of the surgical buttress 110 promote tissue ingrowth, and may fill with blood thereby improving clot integration into the surgical buttress 110. The relatively thin construction of the porous film layers 112 renders the surgical buttress 110 flexible and more easily penetrated by staples and a stapler knife blade. As described above, the openings 114 and/or voids (not shown) of the surgical buttress 110 may be loaded with filler material(s).

FIG. 3 illustrates another exemplary surgical stapling apparatus or surgical stapler 200 (i.e., a linear stapler) for use in stapling tissue and applying a surgical buttress 210 to the tissue. Surgical stapling apparatus 200 generally includes a handle 220 having an elongate tubular member 222 extending distally therefrom. A jaw assembly 230 is mounted on a distal end 224 of elongate tubular member 222. Jaw assembly 230 includes a staple clinching anvil jaw member 232 and a receiving jaw member 234 configured to receive a staple cartridge assembly 236. Jaw assembly 230 may be permanently affixed to elongate tubular member 222 or may be detachable and thus replaceable with a new jaw assembly 230. Staple clinching anvil jaw member 232 is movably mounted on distal end 238 of jaw assembly 230 and is movable between an open position spaced apart from staple cartridge jaw member 234 to a closed position substantially adjacent staple cartridge jaw member 234. A surgical buttress 210 is releasably attached to the staple cartridge assembly 234 and/or the anvil jaw member 232.

Surgical stapling apparatus 200 further includes a trigger 226 movably mounted on handle 220. Actuation of trigger 226 initially operates to move anvil jaw member 232 from the open to the closed position relative to staple cartridge jaw member 234 and subsequently actuates surgical stapling apparatus 200 to apply lines of staples to tissue. In order to properly orient jaw assembly 230 relative to the tissue to be stapled, surgical stapling apparatus 200 is additionally provided with a rotation knob 228 mounted on handle 220. Rotation of rotation knob 228 relative to handle 220 rotates elongate tubular member 222 and jaw assembly 230 relative to handle 220 so as to properly orient jaw assembly 230 relative to the tissue to be stapled.

A driver 250 is provided to move anvil jaw member 232 between the open and closed positions relative to staple cartridge jaw member 234. Driver 250 moves between a longitudinal slot 252 formed in anvil jaw member 232. A knife (not shown) is associated with driver 250 to cut tissue captured between anvil jaw member 232 and staple cartridge jaw member 234 as driver 250 passes through slot 252.

Reference may be made to commonly owned U.S. Pat. Nos. 6,330,965 and 6,241,139, each to Milliman et al. and entitled “Surgical Stapling Apparatus,” the entire contents of each of which is incorporated herein by reference, for a detailed discussion of the construction and operation of a linear stapling device.

Surgical implants in accordance with the present disclosure may also be utilized to repair tissue defects, such as hernia repair procedures. As illustrated in FIG. 4, a hernia repair device 310 includes a first porous film layer 312 a, a second porous film layer 312 b, and a third porous film layer 312 c, each overlying one another. Each porous film layer 312 a-312 c includes openings 314 a-314 c, respectively. The second porous film layer 312 b is sandwiched, or interposed, between the first and third porous film layers 312 a and 312 c. The first, second, and third porous film layers 312 a-312 c are joined at attachment points 316 and define voids 318 between the successive layers. In embodiments, the second porous film layer 312 b may be fabricated from a material having a higher modulus of elasticity than the first and third porous film layers 312 a and 312 c to create a stiffer material that may act as a reinforcing layer to the surgical implant 310, and minimize or prevent implant shrinkage that may occur with the use of fibrous hernia repair devices. The first and third porous film layers 312 a and 312 c may be fabricated from a more flexible material that is more pliant than the second porous film layer 312 b to reduce tissue abrasion and increase patient comfort.

FIG. 5A illustrates an embodiment of a surgical implant including varying degrees of porosity. Surgical implant 410 includes a first porous film layer 412 a configured to be placed against an abdominal wall, a second porous film layer 412 b, and a third porous film layer 412 c configured to face the viscera. Each porous film layer 412 a-412 c includes openings 414 a-414 c, respectively. The first porous film layer 412 a includes a relatively larger degree of porosity to encourage tissue ingrowth therein, while the third porous film layer 412 c includes a relatively smaller degree of porosity to discourage tissue ingrowth and adhesion of tissue thereto. The second porous film layer 412 b may include any degree of porosity.

In embodiments, as illustrated in FIG. 5B, the third porous film layer 412 c may be coated with a hydrophilic adhesion barrier layer 411 formed from a quick dissolving or rapidly bioerodible polymeric material so that any formed adhesion will detach from the surgical implant 410 once the adhesion barrier layer 411 dissolves. Examples of quick dissolving or rapidly bioerodible polymer materials include water soluble polymers such as poly(lactide-co-glycolide)s, polyanhydrides, polyorthoesters, polyvinyl alcohol, hydroxylpropyl methylcellulose, and carboxymethyl cellulose; biopolymers such as sugars, starches, salts, and gelatin; and derivatives and combinations thereof. In embodiments, the openings 414 a and/or voids 418 of the surgical implant 410 may be loaded with filler materials (not shown) as described above. In any of the embodiments described herein, the implant can have voids that have different kinds of filler materials inside. E.g., a hemostat in one pocket and a cancer treating agent in another pocket. For example, one would fill the first pocket by capillary action, then dry the material, and then fill the second pocket with a different material.

It should be understood that while the attachment points are shown as uniting all of the layers of a surgical implant at a common point, the attachment points may be distributed in a variety of patterns, such as only between two successive layers, between all stacked layers, and combinations thereof. As illustrated in FIG. 6, for example, surgical implant 510 includes first and second porous film layers 512 a and 512 b joined at attachment points 516 a and including voids 518 a therebetween. The third porous layer 512 c is attached to the second porous layer 512 b at spaced attachment points 516 b joining all three layers 512 a-512 c along, for example, a periphery of the surgical implant 510, thereby creating, if desired, larger voids 518 b between the second and third porous film layers 512 b and 512 c. The attachment points can be lines, dots, or have any shape.

Surgical implants in accordance with the present disclosure may also be utilized in reconstructive surgical procedures. As described above, mechanical properties of each porous layer, and thus the surgical implant, may be controlled by selecting, among other things, the materials, thickness, and pore density of each porous film layer. In embodiments, the production and assembly of the porous film layers may be tailored to provide improved size retention, toughness, and strength. The films may be drawn, stretched, molded or extruded under conditions, e.g., heated, ambient, or cooled temperatures in a machine and/or transverse direction, to produce films having different molecular orientation structures, and thus different film properties. The porous layers, each having different axial polymer chain alignments, may be stacked to produce a surgical implant having strong tensile properties in multiple planes. For example, FIG. 7 illustrates a surgical implant 610 including a first porous layer 612 a having molecules uniaxially oriented in a machine direction “M”, joined with a second porous layer 612 b having molecules uniaxially oriented in a transverse direction “T”. It should be understood that a surgical implant may also include biaxially-oriented films and/or films that have been incrementally stretched.

Surgical implants of the present disclosure may be utilized as scaffold materials for tissue regeneration. In embodiments, the porous layers of the surgical implant may be optimized for strength to support load bearing application and for cell attachment and ingrowth by providing a combination of porous layers of different thicknesses and surface areas. For example, FIG. 8 illustrates a surgical implant 710 including first and third porous film layers 712 a and 712 c of substantially the same thickness “T1” and “T3” disposed on opposing sides of a second porous film layer 712 b having a thickness “T2”, that is greater than thicknesses “T1” and “T3”. Openings 714 a and 714 b provide the first and third porous film layers 712 a and 712 c with a textured surface with increased surface area for improved tissue integration.

In embodiments, the openings and/or voids may be loaded with filler materials, as discussed above. For example, the openings and/or voids may be loaded with adhesion protein or heparin sulfate conjugated hydrogels or charged beads, that recruit specific cell types and growth factors to encourage cellular ingrowth and maturation. The surgical implants may also be filled with growth factors or anti-inflammatory drugs to improve tissue regeneration.

Surgical implants of the present disclosure may also be utilized for hemostasis. As illustrated in FIG. 9, a surgical implant 810 in the form of a hemostatic patch may include a first porous film layer 812 a configured to face a wound and a second porous film layer 812 b. The first porous film layer 812 a may include an adhesive layer 811 to aid in the attachment of the surgical implant 810 to the wound. In embodiments, the adhesive layer may be a reactive adhesive material that includes functional groups for binding or attaching the surgical implant 810 to tissue by crosslinking with the reactive functional groups present in tissue, such as primary amine groups, secondary amine groups, hydroxyl groups, carboxylic groups, sulfonic groups, combinations thereof, and the like. In embodiments, the reactive adhesive layer 811 may be an in situ polymerizable hydrogel, e.g., commercially available products such as FOCALSEAL® (Genzyme, Inc.), COSEAL® (Angiotech Pharmaceuticals), and DURASEAL® (Confluent Surgical, Inc).

While the first porous film layer 812 a includes a sufficient number of openings 814 a to allow for blood to infiltrate the surgical implant 810, such as through capillary or microfluidic filling, the second porous film layer 812 b includes a minimal number and size of openings 814 b to allow for the transfer of gases while encouraging blood retention in the surgical implant 810. In embodiments, absorbent materials could be included in the openings 814 a, 814 b and/or voids 818 of the surgical implant 810. Absorbent materials, e.g., hydrogels, allow collected blood and other wound fluid to gel and/or solidify thereby consolidating and containing these fluids in the surgical implant 810. Absorbent materials may swell during blood absorption, thereby exerting pressure on the wound to further reduce bleeding.

Surgical implants of the present disclosure may be utilized as a sealant or tissue patch, for example in duraplasty or lung sealant applications. As discussed with respect to FIG. 9 above, a first porous film layer 812 a may include an adhesive material 811 for attachment to tissue, and a second porous film layer 812 b may include a minimal number of openings 814 b to provide a liquid sealed barrier. The porous film layers 812 a and 812 b would allow fluid filling or tissue ingrowth over time thereby encouraging integration into surrounding tissue.

In embodiments, a surgical implant may be fabricated with porous film layers that match the elastic behavior of the tissue in which the surgical implant is placed. For example, in a lung sealing application, the porous film layers of a surgical implant may be formed of elastomeric degradable polymeric materials, such as polyurethanes, to substantially match lung elasticity and to be distensible during lung inflation and retraction during breathing.

In any of the embodiments disclosed herein, the film material can be a combination of biodegradable materials, a combination of non-degradable materials, or a combination thereof. In at least certain embodiments, it is preferred that both layers are made from biodegradable materials. It is contemplated that each of the first porous film layer and second porous film layers are both fabricated from at least one biodegradable material, from different biodegradable materials, from one biodegradable material and one non-biodegradable, or from at least two non-biodegradable materials.

While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the present disclosure, but merely as exemplifications of embodiments thereof. It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications within the scope and spirit of the claims of the present disclosure. 

What is claimed is:
 1. A surgical stapling apparatus comprising: a handle assembly; a tubular body portion extending from the handle assembly; a staple cartridge assembly extending from the tubular body portion; an anvil assembly coupled to the staple cartridge assembly and movable relative thereto between open and closed positions; and a surgical buttress releasably attached to the staple cartridge assembly or the anvil assembly, the surgical buttress including first, second, and third porous film layers successively stacked on each other and interconnected at a plurality of attachment points that define a plurality of pockets between the first and second porous film layers and the second and third porous film layers, wherein the plurality of attachment points between the first and second porous film layers of the surgical buttress are different from the plurality of attachment points between the second and third porous film layers of the surgical buttress such that the plurality of attachment points form at least one of the plurality of pockets between the first and second porous film layers that is different in size from at least one of the plurality of pockets between the second and third porous film layers.
 2. The surgical stapling apparatus of claim 1, wherein the first and second porous film layers of the surgical buttress are substantially planar.
 3. The surgical stapling apparatus of claim 1, wherein the surgical buttress includes a filler material disposed within at least one of the plurality of pockets defined between the first and second porous film layers.
 4. The surgical stapling apparatus of claim 3, wherein the filler material is a drug.
 5. The surgical stapling apparatus of claim 3, wherein the filler material is a hydrogel.
 6. The surgical stapling apparatus of claim 3, wherein the filler material is an adhesive.
 7. The surgical stapling apparatus of claim 1, wherein the first and second porous film layers of the surgical buttress are bonded together at the plurality of attachment points.
 8. The surgical stapling apparatus of claim 1, wherein the first porous film layer of the surgical buttress has a first thickness and the second porous film layer of the surgical buttress has a second thickness that is different from the first thickness.
 9. The surgical stapling apparatus of claim 1, wherein the first porous film layer of the surgical buttress has a first modulus of elasticity and the second porous film layer of the surgical buttress has a second modulus of elasticity that is different from the first modulus of elasticity.
 10. The surgical stapling apparatus of claim 1, wherein the first porous film layer of the surgical buttress has a first degree of porosity and the second porous film layer of the surgical buttress has a second degree of porosity that is different form the first degree of porosity.
 11. The surgical stapling apparatus of claim 1, wherein the surgical buttress further includes an adhesive layer applied to an outer surface of the first porous film layer.
 12. The surgical stapling apparatus of claim 1, wherein the surgical buttress includes a central aperture defined therethrough.
 13. The surgical stapling apparatus of claim 12, wherein the anvil assembly includes an anvil member and a shaft, the surgical buttress positionable on the shaft of the anvil assembly.
 14. The surgical stapling apparatus of claim 1, wherein each of the first and third porous film layers of the surgical buttress has a first thickness and the second porous film layer of the surgical buttress has a second thickness that is greater than the first thickness.
 15. The surgical stapling apparatus of claim 1, wherein the second porous film layer of the surgical buttress is fabricated from a material having a higher modulus of elasticity than materials of the first and third porous film layers of the surgical buttress. 